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y NUT MH) BOLT. Nm 273,233 a Faasmze Mmm 1.31883-l UNITEn STATES PATENT @Erica HAYWARD A. HARVEY, or ORANGE, NEW JERSEY.

NUT AND BOLT.

SPECIFICATION forming part of Letters Patent o. 273,731, dated March 13, 1853. Application led February 2, i883. (No model.)

To all whom it may concern.-

Be it known that I, HAYWARD A. HARVEY, of Orange, New Jersey, have invented a certain Improvement in Nuts and Bolts, of which the following is a specification.

My invention relates to the combination of a screw-bolt with anut having a thread ot'uniform pitch a-nd depth, which thread is truncated in one portion of the nut andl merges gradually into a V-thread or into a more narrow truncated thread in the remaining portion of the nut.

ln Letters Patent ot the United States No. 224,591, dated February 17, 1880, granted to meforau improvementin lock-nuts, l described what I have called a spiral-wedge nut having formed in it a truncated thread which gradually merges into a V thread, the grooves of its truncated thread being progressively deepened for the purpose of providing space to receive the metal of the bolt-thread, which, by the inuence of the truncated thread', when thenut is applied, is forced In Fig. 2 of the drawings of the said patent deepened.

there is shown apartially-iuished spiral-wedge nut which is ready for the final operation of having the grooves of its truncated'V thread It has a thread of uniform pitch, which'at one end is truncated, andwhich, by having its convolutions progressively narrowed at their apices, gradually merges into a V-thread; but the thread is of uniform depth. This unfinished nut of my former patent -is applicable to my present invention, which consists in the combination of a spiral-wedge nuthavinga'thread of uniform depth and pitch with ascrew-bolt the thread of which has the same pitchfas that of the nut, but is in a prescribed degree of less area in solid cross-sec# tion than the transverse area of the grooves between the convolutions of the engaging or V thread of the nut, and is of the same or nearly the same area in solid cross-section as the transverse area of the grooves between the wider truncated convolutions of the nutthread.

The accompanying drawings, illustrating a nut and bolt embodying my invention, are as follows: l,

Figurelis an axial section of' a nut and a po1' tion cfa bolt, showing the bolt partially enlaterally outward.

the nut. Fig. 4 is a section similar to Fig. 3,

except that it represents the bolt as fully entered into the nut.. Fig. 5 is an axial section of a nut and portion ot'la. bolt, showing the applicatiouof my invention to a bolt having a truncated thread with a flat-bottomed groove.

The section-a of the nut is provided with what I call the engaging threads, which may be of V shape or of any other suitable shape, so that this section of the nutvwlll lit the bolt. with comparative looseness." The convolutions of the thread of the middle section, b, ot' the nut, bythe progressive widening of their apices, are gradually merged into the truncated thread c. The boltd is provided with a thread, e,the"convo1utions of which are of less area in solid cross-section than the transverse area of the grooves between the couvolutions of the engaging thread a of the nut. This difference in the solid cross-area ot the bolt-thread may be effected as shown in Figs. land 2 ot' the drawings, in which, as will be seen, the bases of the convolutions of the bolt-thread, prior to the application of the nut, are of the same widthas the width ofthe spaces between the apices ofthe convolutions ofthe V-thread ofthe nut; but the apices of the convolutions of thebolt-tbread are iiattened, making what is known as a truncated thread. There is thus let't'an unoccupied space between theapex of thebolt-thread and the bottom of the V -groove ofthe engaging thread a of the nut. p

Another mode of making the area of the bolt-thread in solid cross-section less than the transverse area of the grooves between the tl-threads of the nut, which may be adopted without departing from my invention, isillus'- trated in Figs. 3 and 4, in which, as wiil be seen, one side of the bolt-thread has the same angle as the side of the V-thread of the nut, While the other side of the bolt-thread is less steeply inclined, thus leaving an unoccupied triangular space bounded by the less steeply inclined side of the bolt-thread and a small Ils 2 Y I 273,73 l

e is applied to the bolt the bases of the boltthreadare progressively compressed by and exert compression upon the spiral-wed ge section b of the nut-thread, and the metal of both threads is thus displaced until, when the nut is fully applied, as shown in Fig. 2,the threads lare so far transformed as `to till or nearly till the grooves'in which they are respectively deposited.v v

Fig. 5 illustrates the marinier in which my invention may be employed in connection with a bolt having a truncated thread with, at-

bottomed grooves between its convolntions'.

u Referring to the structures shown in Figs. 1, 2, 3, and tof the drawings, it will be seen that the engaging-threads et of the nut'are pointed at their apices andhave VLshaped grooves.

' 1n 'the modification illustrated in Fig. 5 the engaging threads of the nut,insvtead ot' being V-threads, are truncated. The other portions of thev nut-thread are therefore made correspondingly thicker in solidcross-sectiou as compared with the threads of the nuts shown in Figs. 1', 2, 3, and #L f A 1n either of these modes ot' employing my invention there is a mutualabrasion ot' the opposed surfaces of the wider truncated thread of the nut and the thread ot' the bolt, with the result that the nut acquires such a rm hold of the bolt that no jarring will release it, and it can only be unscrewed from the bolt by the application of a torsional strain substantially equal to'that employed in screwing it on the bolt in the iirst instance.

What I claim as my inventionisrllhe nut and bolt mechanism herein shown and described, which consists of a nut having formed in it ascrew-thread of uniform depth and pitch, the convolutions of which at one yend, c, are truncated, while in the middle section, b, of the nut, by the progressive `narrowing ot the apices ot' the convolutions,the.

thread gradually merges into eithera V-thread or into a relatively narrower truncated thread, a suitablenumber ofconvolutionsot which, a., are employed -as engaging threads for a screwbolt, the thread of which is, in a prescribed degree, ot' less area in solid cross-section than the transverse area of the grooves between the engaging threads a of the nut, and is ot' the saine or nearly the same -area in solid cross-section Aas the transverse area of the grooves between the truncated convolutionsc ot' the nut-thread.

1L A. HARVEY.

Witnesses y M. L. ADAMS, u

ASA FARE. 

